Why? Ryan gave Thompson a shout-out at a Badger State homecoming rally Sunday, and the former governor quickly incorporated the veep pick's endorsement-of-sorts into a campaign ad.

Those who deal in empirical evidence, however, are not so easily convinced that Thompson rode Ryan's words to the win.

"I'm skeptical," Charles Franklin, director of the Marquette Law School poll, told us Wednesday. "In our final poll, we showed Thompson at 33 percent nine days out from the election. He received 34 percent." The Marquette poll also accurately predicted the order of finish.

About other polls that had Thompson trailing, Franklin said this: "Do you really believe there was a last-second dynamic, and that the [Ryan] shout-out moved Thompson's number by several percentage points?"

Good question.

So, whether Thompson, 70, managed to either hang on to a lead, or surge to the win Tuesday night, he now faces a well-financed and well-known opponent in Democratic Rep. Tammy Baldwin, 50, in a race that will help determine the balance of power in the Senate.

Recent polls that tested a head-to-head matchup between the two candidates looking to succeed retiring Democratic Sen. Herb Kohl have given Thompson a slight edge. But it's less, Franklin says, than one might expect, "given his history as the most popular governor in state history."

Marquette will have new poll results out next Wednesday, he says, that will measure not only the Thompson-Baldwin race but also where the presidential race stands in Wisconsin after Romney's pick of native son Ryan.

Lines Of Attack

In a statement released after Thompson's victory, Baldwin made clear she plans to use the former governor's recent-year lobbying career against him.

Said Baldwin:

"Tonight, the Republican primary electorate presented Wisconsin voters with a clear choice for the November election. Make no mistake, Tommy Thompson will stand with those who already have too much power and influence in Washington."

"I will fight to do what's right for the middle class and Thompson will put those at the very top and the big monied special interests in Washington ahead of Wisconsin's hard-working families. I will take on these powerful interests in Washington, and in the Senate, I will stand up for Wisconsin's middle class, as I always have."

After a career in the Wisconsin state Assembly, Thompson served 14 years as governor before becoming health and human services secretary in President George W. Bush's administration.

He launched a failed bid for the 2008 GOP presidential nomination and has since had what PolitiFact characterized as a "lucrative private-sector affiliation with dozens of health and other companies," including those he oversaw as a member of the Bush administration.

Republicans are focusing on Baldwin's well-established liberal record and her support of Obama administration initiatives including the stimulus and the health care overhaul.

WisPolitics.com, one of the state's go-to political sites, reported Wednesday that Karl Rove's Crossroads GPS has already begun a one-week, $250,000 ad campaign targeting Baldwin. The site's Election Blog reports on the ad:

"The narrator says Baldwin voted for the 'failed' $1 trillion stimulus package, which included projects like $800,000 to replace light bulbs, and the national debt has increased more than $10 trillion since she went to Congress."

"'Tell Tammy trillions wasted is too much. Stop the wasteful spending and cut the debt,' the narrator says before encouraging viewers to support the 'New Majority Agenda.' "

Money Race

Franklin, of Marquette, says that Baldwin, who did not have a primary opponent, has raised nearly three times as much money as Thompson.

On Wednesday, former Wisconsin Democratic Sen. Russ Feingold and his political action committee, Progressives United, launched what it calls a "Cheddarbomb" to add to her coffers.

The Center for Responsive Politics reports that Baldwin this cycle has raised $7.1 million and has $3.1 million cash on hand. Thompson has raised $2.4 million and has $352,915 cash on hand.

Thompson has some work to do, but though there are fractures in the Republican Party, Franklin says, "it will surely unite behind him against Baldwin."

"There is still residual good feeling from his time as governor, and that's an asset," he says, "though we don't want to overstate it."

Mike Tate, chairman of the Wisconsin Democrats, indicates his party will make sure that it's not overstated.

"It's been a long time since Tommy Thompson has been in Wisconsin," Tate said Wednesday. "He sold out, left Wisconsin and is too out of touch to fight for Wisconsin."

For a state that has been at the epicenter of politics and political battles over the past two years, yet another has now been joined.

Other GOP Primary Races

The biggest primary shock Tuesday came out of Florida, where long-serving GOP incumbent Rep. Cliff Stearns was upended by veterinarian Ted Yoho, who rode Tea Party support to victory. The stunned Stearns, known for his pursuit of the Obama administration's investment in the failed solar energy company Solyndra and for advocating the defunding of Planned Parenthood, conceded Wednesday.

Also in Florida, in a battle of two GOP incumbents, Rep. John Mica, who chairs the House Transportation and Infrastructure Committee, easily defeated Rep. Sandy Adams, who had Tea Party support.

In Connecticut, pro-wrestling mogul Linda McMahon succeeded in her effort for a second shot at a seat in the U.S. Senate. The Republican McMahon obliterated former GOP Rep. Christopher Shays, winning her party's nomination for the U.S. Senate seat being vacated by independent Sen. Joe Lieberman.

In 2010, McMahon used $50.1 million of her own money in a losing Senate race against Democrat Richard Blumenthal. This cycle, she has raised $14 million, which includes just $7 million of her own money. So far.

This fall she'll face three-term U.S. Rep. Chris Murphy, who coasted to victory in his Democratic primary.